From owner-freebsd-net@freebsd.org Mon Mar 13 07:50:42 2017 Return-Path: Delivered-To: freebsd-net@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 401CED0AA75 for ; Mon, 13 Mar 2017 07:50:42 +0000 (UTC) (envelope-from akoshibe@gmail.com) Received: from mail-qt0-x234.google.com (mail-qt0-x234.google.com [IPv6:2607:f8b0:400d:c0d::234]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id EC67EAE7 for ; Mon, 13 Mar 2017 07:50:41 +0000 (UTC) (envelope-from akoshibe@gmail.com) Received: by mail-qt0-x234.google.com with SMTP id i34so25870716qtc.0 for ; Mon, 13 Mar 2017 00:50:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:from:date:message-id:subject:to; bh=B5yHx23JfNaMEabbNZYV0tKgtADtrl7BnxvLTFb0Jyo=; b=i6mWOu0ywzLe+DfR+27Jwgv8VkvE6aycBXVsI+YIYyLhiUn8sPzXCIPa+2y9rd59nU wTarRpl6zaUJ6Ge7D1aONapr8AZM5PvduII/KdVTtVlDfzGudd/Vh+mSS82D5m5eWdu5 +Gbu32Zklb1T45UyvtnNY2i+8XOaF4mBVgQ4xrYaXVgVdhEDvwT7InC2dN86PJlqATK6 WZFKSTR/z3mqRtg4EZNBgzZeZWnYLBCYpFLsPuceieg/a+oWE5rs0yD3UP+zWR1dYq8W vFJZNoEKMIim9Q8AUIkkCg7s1u9pi+W3R2FqmgFSd4sr37nQp8pSAnyVKr0RtUpvoPr9 WfqA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:from:date:message-id:subject:to; bh=B5yHx23JfNaMEabbNZYV0tKgtADtrl7BnxvLTFb0Jyo=; b=sNjtcphkpg46KDRxK1zIv1B5pfsoqW1KTmPTmUrK7XMElBaWO83PFARgFcDYd43fmT I2LtwFAWB40XQK0gIAgQgqAYwj2JHqgSw4bayNqBB7bf7xAac3a+oIe9LXhOD9L5iv38 4sF4qjkgJz7IUSZZW98a9mCr1X6z00K8Ncj8PU2U/l9/YntuZMfo0LcNjKwVRp0f6Rab Jf5HmT7C5E/bkmQXzPLHFfj7ZFSsH5LyiKH8D/fQaNvjprsgB5poFmgHiuw4ZsqWztfb nLY8eiAb+vldTFzKoomE1d8nCZuqlj6XWhExrN0nT8kzjCt0F4f8S8Z0xoRmojVgQGgV CZLg== X-Gm-Message-State: AMke39mv+wzEKkRNwd0QF2n2WBhbMHiXIgM5RyhyVixyCHczMP2lk1tig+c5Di/BesSP5kccanxGQGvx8ksCsQ== X-Received: by 10.200.52.196 with SMTP id x4mr33333788qtb.276.1489391440449; Mon, 13 Mar 2017 00:50:40 -0700 (PDT) MIME-Version: 1.0 Received: by 10.140.17.14 with HTTP; Mon, 13 Mar 2017 00:50:40 -0700 (PDT) From: Ayaka Koshibe Date: Mon, 13 Mar 2017 00:50:40 -0700 Message-ID: Subject: BPF departure handler and interface renaming To: freebsd-net@freebsd.org Content-Type: text/plain; charset=UTF-8 X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 13 Mar 2017 07:50:42 -0000 Hi, I had submitted a PR for a panic caused by Open vSwitch a while back: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=213015 It looks to be due to traffic being sent while a tap interface is being renamed, during which if_bpf in the ifnet is set to null. The following patch does stop the panic (it's also been added to the PR). I see similar checks in some other departure handlers like lagg and vxlan - so I'm wondering if this would be a sensible check here. Thanks. Index: net/bpf.c =================================================================== --- net/bpf.c (revision 313973) +++ net/bpf.c (working copy) @@ -2678,6 +2678,9 @@ struct bpf_if *bp, *bp_temp; int nmatched = 0; + if (ifp->if_flags & IFF_RENAMING) + return; + BPF_LOCK(); /* * Find matching entries in free list.